New approach for deep brain stimulation?

What is deep brain stimulation?

Deep brain stimulation (DBS) emerged as a treatment for people with Parkinson's in the 1990s. The first systems treated refractory tremors, and a few years later were also approved for treating people with advanced disease suffering from symptoms that could not be controlled by medicines alone.

The folks who first called this treatment "deep brain stimulation" were not the marketers. Its was described as drilling a hole through the skull so that a long, almost rigid wire could be passed from the brain surface into the deep brain structures where electrical impulses would stimulate a very specific part of the brain. The first people that had the procedure were very brave, as is the case with any new treatment. Hard to imagine volunteering for the procedure in the early days unless I had Parkinson's that made me incredibly miserable. Of course, that is what Parkinson's does eventually.

People are more familiar with a pacemaker for heart disease than DBS for Parkinson's disease. Think of DBS as a pacemaker for the deep brain structures - the part of the brain that controls bodily functions, not the part we use to think. When used in the brain, this device puts out electrical impulses at a much faster rate than when a pacemaker is used to support heart function. In its basic form, it is tech that is repurposed from the heart to the brain, albeit with a ton of work completed to enable that shift to happen.

A prominent benefit of deep brain stimulation is its control of debilitating tremor. Here's one video example of how the stimulator can be adjusted to completely stop the tremor - allowing for normal movement.

Today's DBS systems are useful to improve symptoms of Parkinson's disease, but do not reverse the disease or eliminate the need for medical therapies.

Can DBS therapy be meaningfully improved?

In a study published in Nature Medicine last month, Dr. Oehrn and colleagues took a new approach. Instead of implanting a DBS system and turning it on, they studied whether they could figure out how to make the DBS system adapt to a person's needs automatically. This study in 4 people feels to me like the shift from a hand-held calculator to a programmable computer.

They were able to identify the brain signals that related to when movement was good and when it was bad as well as when the dopamine levels were higher or lower. With that information, the DBS system could be programmed to respond automatically and provide electrical impulses when movement was more impaired, which correlated with times that dopamine levels were not at their peak.

It is not possible to know whether this will be a major step in DBS therapy. After all, DBS works because the electrical stimulation provides dopaminergic stimulation. As you know from prior posts, my interpretation of the science is that dopamine levels are too high, and therefore, I am not a fan of DBS as a long-term therapy for Parkinson's (with exceptions such as debilitating tremors). Similar to the limited duration of controlled studies with standard DBS (no controlled trials have studied the therapy for longer than 6 months), this feasibility study tested this "smart" DBS for only a month. While that is the right place to start, we need controlled trials longer than that to understand the long-term effects of the therapy.

I want to be optimistic that this is the start of a breakthrough, but even if it were, there are problems. DBS remains a therapy with significant risks. And based on the randomized clinical trials and the product labels, DBS is more useful for debilitating tremors than for slowed movement or rigidity. Hopefully I am proven wrong in my skepticism of DBS as an answer for the broad population of people with Parkinson's.